Transparent Interconnection of Lots of Links (TRILL) is a Layer 2 (L2) network standard recommended by Internet Engineering Task Force (IETF), and may make up for the lack of Spanning Tree Protocol (STP) in a large data center.
In a TRILL network, a device running TRILL protocol is called a Routing Bridge (RB), and each RB has a unique nickname. The first RB that a unicast frame encounters in a campus in the TRILL network encapsulates the frame with a TRILL header that specifies the last RB where the frame is decapsulated. To save room in the TRILL header and simplify forwarding lookups, a dynamic nickname acquisition protocol is run among the RBs to select 2-octet nicknames for RBs. The nicknames are used to specify the ingress and egress RBs in the TRILL header.